Blood flows against gravity in the arms and legs and other body parts and is prevented from flowing back by

Options :
  1. the extremely low pressure of venous blood
  2. valves
  3. movements in the surrounding muscles
  4. the narrowing down of the lumen of veins by the contraction of the muscle layer comprising their walls

Answer and Explanation :-

Answer: Option 2


Sorry there is no explanation for this answer. Please help others by posting your response below

How do you rate this queston?  Very Easy  Easy  Average  Above Average  Tough

Previous Question : In order to cure certain diseases of blindness, which part of the donor's eye is used for grafting?

Next Question : Which of the following is the average weight of a human male brain?

Click here for online test on General Science


 (Getemail alerts when others member replies)

If people refuse to look at you in a new light and they can only see you for what you were, only see you for the mistakes you've made, if they don't realize that you are not your mistakes, then they have to go.
-Steve Maraboli Life the Truth and Being Free